Lens-grinding machine.



H. 0. GOWLLAND. LENS GRINDING MACHINE. y

APPLICATION FILED OCT. 9, 1915 I, I I 1,217,090. Patented Feb. 20,1917,

M'mEss s UNITED STATES Pa TENT OFFICE.

HENRY 0. GOWLLAND, 0F MONTREAL, QUEBEC, CANADA, ASSIGNOR TO NATIONAL TRUST COMPANY, LIMITED, (IN 'rnos'r.)

LENS-GBINDI-NG MACHINE.

Application filed October 9, 1915.

To all whom it may concern:

Be it known that I, HENRY Oflownnaxn, a citizen of the Dominion of Canada, and resident of the city of Montreal, in the Province of Quebec and Dominion of Canada, have invented certain new and useful Iin 'provements in Lensdlrinding Machines, of

' that the sudden change in direction of the arm on which the lens is carried, when operating against a rigid tool holder, results in unsatisfactory grinding, the chief characteristic of which is a wavy surface. To overcome this disadvantage, I provide a re silient or yielding tool holder which will give slightly when the lens holding device changes direction, thus overcoming the unequal pressure of the lens and eliminating the wavy grinding which ordinarily results.

The resilient. holder consists briefly ofa fixed pedestal and a tool-holder connected with the pedestal by a ball and socket joint.

A plurality of springs are mounted between the pedestal and tool holderaround the ball and socket joint to normally maintain the tool holder in predetermined position. A suitable bellows arrangement may be con.- nected between the pedestal and tool holder for the purpose of excluding grit from the springs and ball and socket joint.

In the drawings-which illustrate the invent1on:-

Figure I is a vertical sectional. view of the estal 12 of the tool holder'is revolubly andslidably mounted, and in which it may be locked at any desired adjustment by means of the set screw 13. The upper end of the pedestal carries a table 14 preferably'circuor in form, iii the center of which a sphere Specification of Letters Patent.

Patented Feb. 20, 1917.

Serial No. 55,025.

1:) is mounted on the short neck 16, of a diamcter ccmsiderably less than the diameter of the sphere. The tool holder proper romprises a plate 17 preferably circular in form,

pnd 0'? the same size as the table ll. and ha in projecting from the lower surfacithereof a centrally disposed hollow neck l(\ c.\'-- tcrnally throa h=d for the reception of a nut 19. The neck 18 and nut 19 are provided with surfaces 20 ground to spherical clu'\'a-.

ture conforming exactly to the sphere 15, so that the tool holder will have free oscil lating movement in any direction. The bore of the neck 18 above the sphere 15 forms a.- reservoir 21 for the reception of a lubricant which may be inscr ;d by removal. of'the filling plug 22. The upper surface of the plate 17 is provided with avholloui neck 23, in

which the grinding tool 27+, may -lo mounted by means of set' screws 25. Adjacent their peri fiheries, the plate 17 and table H are provided with studs 26 arranged equidis tantly from one another and,"egpiidistantly from the centers of the table 14. and plate 17, those of the table ll'heing upwardly projecting and those of the plate 17 being down \vardly projecting and arranged axially in line with the ones below. The s 'iriugs 27 of equal length and strength are intnlntetl bw tween the table 14 and plate 17 in suitable compression, and are held in position by the studs 26. These springs and their supporting studs are not limited to the number shown, as either a greater or lesser number of same may be used if desired. Peripheries of the table 114 and plate 17 are connected by a bellows 28 of suitable material, which will) prevent an accumulation of dust and. grit from the grinding operations on the springs and ball and socket joint. The lens holder which operates in conjunction with the tool 234: is designated 29 and the lens held thereby is indicated at 30.

The operation of the device is extremely simple.

It will be obvious that when the lens is located (.lirectly above the ball and socket joint, the entire pressure is supported by the joint, but ;that the lens moves toward the periphery of the tool 24, the load. is supported partly by the joint and partly by the springs 27. During the grinding operation, the lens carrier and lens travel'in an irregular path,

which is carefully designed to insure un1-.

changes direction, so thata uniform grindform grinding. The constant changes in direction of the tool have been found to produce an irregular grinding action when the tool is mounted a rigid holder, owing to the \"ariations in pressure occasioned by the change of direction and the curvature of the tool. In the present invention, these changes of pressure are minimized by the resilient mounting of the tool holder, which yields as required when the lens holder ing results. 'Lhetool beingmounted concentrically above the ball and socket joint and the springs being of equal strength and located equidistant from the center, the resiliency of the holder is uniform at all points equidistant from the center.

Haring thus described my in\'ention,wl1at 1 claim is 1. In a device of the class described, a tool holder having a depending socket, a plate supporting pedestal, a ball carried by said plate upon which said socket is adapted to rest, and springs carried near the periphery of said plate, adapted to yieldingly support the peripheral portion of said tool holder. In a device of the class described, a tool holder, a plate supporting pedestal, a rockable connection and yield-able spring supporting said holder from said plate, and a bellows between said holder and said plate. In a device of the character described, an adjustable rigi-dly mounted, pedestal, a tool holder, a ball and socket joint connecting the pedestal and tool holder, springs arranged in uni-forincompression between the pedestal and tool holder, and disposed equidistant from the center of connection, studs on the pedest \l and tool holder maintaining said springs iii position, and a flexible casing connected between the pedestal and tool holder.

In witness whereof, I have hereunto set my hand, in presence of two witnesses.

' HENRY O. GOWLLAND.

itn esses R. \V. ALLEN, G. M. MonELANn. 

